A plurality of projectors (projection type display devices) can constitute a projection display system for displaying an image on a common projection screen. In the above projection display system, a plurality of images produced on the projection screen by a plurality of projectors can be adjusted properly to display a single image.
FIG. 11 is an illustrative diagram showing a conventional projection display system. The system shown in FIG. 11 comprises a stack of three projectors PJZA, PJZB and PJZC. Each projector displays an image based on an analog video signal AV1 supplied by an image supply device (not shown). The three projectors are controlled by a single remote controller 229.
In this conventional projection display systems, however, it is difficult to control each of the projectors PJZA, PJZB and PJZC. For example, when it is desired to control only one of the three projectors, since all of the projectors operate in the same manner in response to operation signals output from the single remote controller 229, control is difficult.